The outer leaflet of the outer membranes of Gram-negative bacteria is almost entirely composed of lipopolysaccharide (LPS) and acts as an efficient permeability barrier against antibacterial agents. Lipid A (endotoxin) functions as the hydrophobic anchor of LPS and is the bioactive component of the molecule leading to Gram-negative septic shock and death. The enzymatic machinery required for lipid A biosynthesis is well understood, however, the enzymes responsible for certain regulated modifications of lipid A remain unknown. These modifications include the addition of 4-aminoarabinose, phosphoethanoiamine, palmitate, 2- hydroxymyristate, phosphate, and the removal of specific fatty acyl chains. It is now known that some of these modifications are important for survival of the bacterium from the host innate immune system. Therefore, understanding the enzymology of these modifications will not only facilitate the understanding of lipid A biosynthesis but will lay the foundation of new molecular insights into pathogenesis. The current study focuses on (I) the characterization of enzymes involved in the addition of 4-aminoarabinose and deacylation of lipid A; (II) structural analysis of the enzymatic products and analysis of their endotoxic activities; and (III) the cloning of these novel genes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32AI010506-02
Application #
6362269
Study Section
Special Emphasis Panel (ZRG1-BIO (01))
Program Officer
Somers, Scott D
Project Start
2001-03-01
Project End
Budget Start
2001-03-01
Budget End
2002-02-28
Support Year
2
Fiscal Year
2001
Total Cost
$40,196
Indirect Cost
Name
Duke University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
071723621
City
Durham
State
NC
Country
United States
Zip Code
27705